


why can't we go on as three?

by enbygoo



Category: TOMORROW X TOGETHER | TXT (Korea Band)
Genre: Anal Fingering, Anal Plug, Anal Sex, Bottom Choi Soobin, Brother/Brother Incest, Brotherly Love, Bruises, Coercion, Come Eating, Come Swallowing, Comeplay, Corruption, Creampie, Deepthroating, Face-Fucking, First Time, Group Sex, Incest, Jealousy, Kissing, M/M, Marking, Mildly Dubious Consent, Nipple Play, Oral Sex, Overstimulation, Pet Names, Pining, Polyamory, Porn With Plot, Porn with Feelings, Sex Toys, Sibling Bonding, Sibling Incest, Sibling Love, Spitroasting, Threesome, Top Choi Yeonjun, Top/Bottom Versatile Huening Kai, Twincest, Underage Kissing, Underage Sex, brief pet play
Language: English
Status: Completed
Published: 2021-01-14
Updated: 2021-01-14
Packaged: 2021-03-17 19:27:23
Rating: Explicit
Warnings: Underage
Chapters: 1
Words: 6,429
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/28730421
Author URL: https://archiveofourown.org/users/enbygoo/pseuds/enbygoo
Summary: twins yeonjun and soobin return home from university for their summer break to discover that not only is their brother not so little anymore, but he's also a lot more fuckable than they remember. the twins decide that it's time to let him in on their little secret.-------------this work is an entry for XTXFEST, hosted by @jvnixt on twitter. the prompt: yeonbin fuck their baby brother kai <3
Relationships: Choi Soobin/Choi Yeonjun, Choi Soobin/Choi Yeonjun/Huening Kai, Choi Soobin/Huening Kai, Choi Yeonjun/Huening Kai
Comments: 3
Kudos: 117





	why can't we go on as three?

**Author's Note:**

> DISCLAIMER: this fic includes incest, coercion, dubious consent, and a character who is vaguely underage. if any of these themes upset or trigger you in any way at all, please DO NOT read this fic. please heed the warnings and stay safe. thank you <3
> 
> for those of you who came/stayed for these themes, happy reading and i hope you enjoy <3 and if you wanna interact with me, hmu on twitter @enbygoo !!

soobin and yeonjun had an extremely close bond, which was just one of the many benefits of having a twin. however, once their baby brother kai came into the picture, the twins vowed to never exclude him from that bond. eventually, their little trio got along so well that most of their family saw kai as an extension of the twins, with some even going so far as to say he was a triplet born too late.

so, when the time came for soobin and yeonjun to move away for school, the triad was understandably crushed. it was particularly difficult on kai, since the eldest boys still had each other. for kai, the whole situation served as yet another painful reminder of what they had all tried so hard to compensate for: a glaring age gap. 

meanwhile, yeonjun and soobin had a different problem. the twins found themselves yearning for a way to exhaust the affectionate, playful energy that they would typically harbour for kai. eventually, they settled on directing this energy towards hooking up with random boys on campus, but it never truly filled the void that kai’s absence created. 

in the weeks leading up to their summer break, the twins found themselves restless at the mere thought of finally being reunited with their baby brother. they spiralled into a myriad of heated debates about who should get to hug the boy first when they arrived home. little did they know that hug would end up being the least of their concerns. 

as soon as yeonjun and soobin crossed the threshold into their family home, an excited kai came barrelling down the hall towards them. kai jumped into the closest boy’s arms, which happened to be soobin.

“hyung!! i missed you so much!” kai bounced up and down excitedly with each word. with flashbacks of kai’s many slips and falls suddenly appearing in his mind, soobin instinctively placed his hands on the younger boy’s ass for support. only this time, soobin’s palms were greeted with significantly more cheek than he remembered feeling before.

“woah! careful there, hueningie! don’t wanna get hurt on our first day back,” soobin managed to choke out despite the oddly placed surge of arousal that was now spreading throughout his body. 

“of course not, hyung!” kai’s eyes lingered a moment too long. the plush skin of soobin’s soft cheeks burned red. soobin needed relief. luckily, yeonjun spoke.

“ahem... you do realize you have another brother, right?” 

“yeonjunie!!” kai quickly jumped down from soobin’s arms and into yeonjun’s, hugging him tightly to make up for the uneven attention. “don’t be jealous. i missed you both so much.” 

“i know, baby. we missed you too.” yeonjun reciprocated kai’s hug with an even tighter squeeze, making the younger giggle before placing him on his feet once again. “so, what does our little hyuka wanna do first? play games? watch a movie? order pizza? your choice!”

kai’s face dropped. 

“um, actually...mom didn’t tell me you guys were coming until today, so i already made plans with beomgyu and taehyun…” the younger trailed off, shame written all over his face. “i wanted to cancel more than anything, but mom wouldn’t let me!! please don’t hate me…”

yeonjun felt his heart clench at the boy’s bittersweet words: it was physically impossible to get mad at kai, let alone stay mad. 

“hey, we could never hate you! listen, we have to unpack anyways. so, go hang out with your friends, and we’ll be waiting for you. just make sure you save some energy for us, huh?” yeonjun gave kai his blessing, adding a wink just to let the younger he wasn’t taking it too seriously. soobin remained suspiciously quiet. 

“oh, don’t worry, hyung. i’ve got lots of pent up energy saved just for you!” kai’s tone was so innocent but the words made yeonjun’s dick twitch. 

kai promptly gathered his things, leaving his brothers high and dry. neither one of them was willing to expose the common cause of their sudden arousal. opting, instead, to head for their old, shared bedroom and blow off some steam, which was the choi twin code for making out.

after a few minutes of sloppy kisses and the occasional hickey, soobin left his spot on yeonjun’s lap to lay beside him on the bed. they stared up at the ceiling, breathless, until soobin broke the silence.

“i never thought in a million years that kai - our baby kai - would get that big…” soobin trailed off in disbelief at the younger boy’s sudden growth spurt. 

“i mean, we should’ve guessed that he’d end up growing into those long limbs some day,” yeonjun said nonchalantly, seemingly not as affected by this revelation as his younger twin. 

“he’s just so cute!” soobin covered his face with a melodramatic sigh. “even though he’s all grown up he’s still a baby, but...oh my god, did you see that ass?!”

“soobin!!” the older sat up and stared at his brother with a mixture of shock and awe. the twins just stared at each other for a moment before yeonjun flashed soobin a mischievous smirk. “yeah, i most definitely saw that ass.”

“oh my god, you too? i thought i was the only one!” soobin’s eyes went wide with realization.

“oh, please, the only one?! i’ve been fantasizing about kai for as long as i can remember. don’t tell me you never wondered why so many of the boys i pick for us to fuck end up looking like kai?” 

“is that why i can’t stop thinking about railing him? because you conditioned me to wanna fuck everything that looks like him?” 

“no, baby. something tells me that desire was always deep inside you. i just helped you realize it,” yeonjun teased. “may i remind you that everytime you nap during our study sessions, i hear every name you moan in your sleep.”

yet another silence ushered itself into the room as soobin processed the complicated emotions that would most certainly come with realizing you’ve always wanted to fuck your baby brother.

“i once heard kai moan beomgyu’s name in his sleep. do you think those two ever fool around?” soobin asked, jealousy evident in his voice.

“i wouldn’t doubt it. he is at the age we were at when we started experimenting with each other.” yeonjun replied, matter-of-factly. “now, if you would have asked about taehyun, then yes.” 

“how are you so sure?” 

“because i also hear kai moaning names in his sleep.”

the twins sighed in unison at the bad sleep talking habit that all three of them had somehow inherited.

“they’re probably making out as we speak…” soobin groaned. 

“soobin,” yeonjun shot the older boy a warning glare. “we haven’t even told him that we like him like that. what do you expect him to do? save his virginity for us?”

“maybe we should,” soobin muttered.

“should what?”

“maybe we should tell him we like him like that...”

yeonjun picked up his phone and held it to his ear. “hello, 911? i think my brother’s erection has finally sucked all the blood from his head and made him lose touch with reality.”

soobin swiftly grabbed the nearest pillow and smacked the phone out of the older boy’s hand, causing yeonjun to giggle mischievously. 

“i’m serious, yeonjunie,” soobin pouted. “i don’t think i’m being as delusional as you think i am. you didn’t see the way the kid looked at me today. there was something different in his eyes...something…”

“horny? yeah, i saw it too. just thought it was your run-of-the-mill hormones. i didn’t think it was directed at us!” argued yeonjun.

“are you so sure that you’re willing to pass up the possibility? don’t you want to share what we have together with him? if we don’t at least offer, it’s just gonna be one more thing that makes him feel excluded from our bond.”

admittedly, soobin’s heartfelt plea started to chip away at yeonjun’s steely resolve. he could feel himself crumbling at the idea of finally being able to worship his baby brother in every. single. way. possible. 

“i’m in,” yeonjun nearly whispered as he stared at the ceiling, unable to make eye contact with his twin. soobin, on the other hand, released a squeal of excitement before throwing himself on yeonjun’s chest and smothering him with kisses.

suddenly, the front door slammed shut and the twins froze. 

“yeonjunie! soobinnie! i’m back!” kai’s sing-songy voice practically floated up the stairs. too bad his only audience was too preoccupied with pulling their shirts back on to enjoy the sweet sound. 

“there you are!” kai exclaimed, blissfully unaware of the scandalous conversation that had just occurred.

“kai, you’re back! where’s mom? did she pick you up?” yeonjun prodded.

“no, i walked home,” kai meandered towards the bed, choosing to squeeze himself into the minimal space between his brothers. “mom had plans, so we have the house to ourselves tonight! isn’t that awesome!”

the twins looked beyond kai to share a perverse, knowing glance before soobin gave yeonjun a nod of approval.

“kai, listen. there’s something that soobin and i want to tell you about. we started doing this... thing together, and we weren’t sure if you’d be interested, but you know we hate excluding you,” yeonjun tried his best to tread lightly into the subject. 

kai just nodded as he was clearly concerned by the sudden shift in mood.

“s-sometimes, soobin and I like to kiss...in more than a brotherly way.”

“w-what do u mean?” kai’s face darkened with confusion.

“well, um…” yeonjun found himself lost for words, which doesn’t happen often.

“let’s just show him,” soobin blurted out. 

the idea took yeonjun by surprise, but it sounded much better than trying to explain. so, yeonjun reached across kai’s lap to grab soobin’s neck and pull him into a loving kiss. the twins made sure to include just enough tongue to demonstrate what a “more than brotherly” kiss looks like. after a few seconds, the twins begrudgingly pulled away to check on their little brother, who had now gone beet red. 

“how do you feel about this, hueningie?” soobin asked, making sure to comfort the flustered young boy with a pet name.

“feels kinda weird. isn’t it um…” kai nervously rubbed his palms on his jeans, “bad for brothers to kiss like that?”

“hueningie, what we do with each other is not normal to other people, but that’s just because they don’t understand it,” yeonjun began the speech that he had always hoped - but never expected - to one day recite for his baby brother. “soobin and i love each other so much that, to us, it feels right expressing that love physically.”

“and you know that we love you just as much, right?” soobin jumped in. kai nodded sheepishly. “so, that’s why we want to share this with you, but only if you want it too.”

“i-i love you both so much...just don’t know...” kai trailed off, visibly conflicted by this new information.

“have you ever kissed anyone like that, hyuka?” yeonjun enquired.

“y-yeah, a few times with beomgyu and taehyun. we couldn’t really figure out how to do it though.”

soobin felt a sense of jealousy bubble up within him at this new information. before he could stop himself, soobin placed a hand on kai’s cheek and gently forced the boy to meet his gaze.

“would you like to try kissing us...like that?” soobin asked with a teasing smirk on his face and kai melted in response.

“y-yes…” the word came out in a desperate whimper, but it was all the twins needed.

soobin’s hand moved to the back of kai’s head to urge the younger boy forward. the moment their lips met, kai froze. soobin softly pecked at kai’s lips, massaging the tension out of them until kai found the confidence to kiss back. once soobin gently licked the younger boy’s lips, kai released a sinful sigh of pleasure and soobin took the opportunity to finally mingle tongues with his little brother. 

the kiss got more natural and heated as the seconds wore on, but soobin knew they had a lot more explaining to do. reluctantly, soobin pulled away from the kiss, giggling slightly when kai leaned in for more.

“good boy, hueningie…” soobin whispered. “but, there’s more that we need to tell you.”

“more?” kai asked between laboured breaths. 

“yes. we don’t just kiss, hyuka. you know how we taught you to touch yourself when you get hard ...down there?” yeonjun took the reigns once again. confusion returned to kai’s face, but he nodded pliantly nonetheless. “soobin and i touch each other when we get hard. have you and your friends ever tried that, baby?”

“n-no, just kisses. i’ve never even seen beomgyu’s uh...down there, and i’ve only seen taehyun’s accidentally.” 

“may i?” yeonjun asked with a warm smile as he let his hand hover over kai’s crotch. kai bit his bottom lip and nodded. yeonjun let his hand rest upon the young boy’s growing bulge before just barely rubbing his palm against the fabric. “i could tell you were getting hard while soobinnie was kissing you. your hips were moving against nothing. it must be really uncomfortable, hm?”

“y-yeah...feels better when..ah...you touch it, hyung,” kai’s squeezed his eyes shut.

“want us to help you feel even better?” soobin blurted out, finding it increasingly difficult to hold back his excitement. 

“w-what do you mean?” kai nervously stuttered.

“why don’t you lay back and get comfortable on the bed first?” soobin directed and the youngest obeyed, turning to crawl up towards the pillows. once the younger boy was comfortable, the twins assumed their respective positions on either side of kai’s legs. 

“hyuka, soobinnie’s gonna take your pants off now, is that okay?” yeonjun spoke as he caressed kai’s cheek. kai looked unsure. “just look at me. hyung is gonna make you feel good, okay?”

“o-okay.”

yeonjun claimed kai’s lips in a loving kiss, trying his best to distract the younger while soobin worked on his belt buckle. suddenly, soobin gasped, causing kai to break the kiss in a panic.

“what? is something wrong?” kai tried to cover his now exposed cock, but soobin was quick to grab his wrists and stop him.

“i just gasped because you’re so beautiful, hueningie. you’ve really grown...everywhere...but you’re still so so pretty,” soobin gushed, a huge smile forcing his deep dimples to appear. soobin couldn’t contain himself at the sight of his baby brother’s cock. he wanted to explode. “so cute!!” soobin suddenly hugged kai’s hips, causing his cheek to press against the hard member in front of him. 

kai threw his head back at the feeling of soobin’s soft, squishy cheek rubbing against him. yeonjun giggled affectionately at his twin’s goofy behaviour. 

“hueningie, we wanna make you feel good with our mouths,” soobin whined cutely. “would you like that? wanna let your hyungs suck your dick?” 

“m-my dick? y-your mouth?” kai stuttered. it’s not like kai was completely unaware of sex. he had ventured onto porn sites a few times and had even heard stories from others in his class. however, this was the first time he had ever heard his beloved brothers discuss it so explicitly. “have you...um...used your mouths on each other before?”

the twins nodded enthusiastically, which lit a familiar fire of jealousy deep in kai’s subconscious. 

“okay, i wanna do it too…” kai whispered, an uncertain determination evident in his voice.

“good boy, hyuka. it’ll feel good, we promise,” yeonjun comforted the boy before leaning down in sync with his twin to lick a stripe up the side of his cock. 

the two started slowly, lapping at the young boy’s length. kai’s hips began to buck subconsciously and the twins took that as their sign to escalate things. yeonjun trailed his way up to the top of kai’s cock before taking the head into his mouth. meanwhile, soobin jumped in between kai’s legs to get better access to the neglected base of his cock. yeonjun quickly lost himself in the sensation of his baby brother’s hard length gliding against his tongue. despite his best efforts to take it slow, yeonjun started practically deepthroating the poor, inexperienced boy, only realizing it when kai let out a particularly tortured moan.

“ye-yeonjun hyung...think i might ..might cum,” kai whimpered as he writhed against the pillows. 

yeonjun and soobin pulled back simultaneously, both of them terrified at the thought of their fun coming to an end so fast. in an attempt to soothe the younger boy, yeonjun caressed and massaged his thighs as he spoke. 

“can you try not to cum for a while, baby? there’s one last thing that soobin and i want to share with you.”

with kai’s approval, soobin moved to cuddle into the younger’s side as yeonjun proceeded to explain their final proposal.

“soobin and i have sex with each other. do you know what that means, hyuka?” yeonjun asked and kai nodded once again. the older noticed how kai moved his hands to rub soobin’s belly, a telltale sign that the young boy was feeling nervous. 

yeonjun reached down beside the bed to pick up one of his duffel bags. after opening the bag, he revealed a myriad of sex toys and laid them out on the bed. 

“these are the toys that we use to stretch ourselves out before we have sex.”

“s-stretch?” kai’s asked in a wavering voice.

“that’s right, baby. we--. well, mostly soobin, uses these toys to stretch his ass before i have sex with him so that it doesn’t hurt.”

“it hurts?” kai’s eyes went wide.

“no, it shouldn’t. that’s why we use the toys and lots of lube, so that all you feel is pleasure. we would never hurt you, baby. we love you.”

kai’s nervous gaze fluttered between his two older brothers. while kai detected nothing but love in their eyes, he remained fearful at the mere possibility of pain.

“so, you want to have sex with...me, which means that i have to stretch myself out?” kai clarified and yeonjun nodded.

“but we’ll help you with everything and make sure you feel good the entire time,” soobin reminded kai before leaving a few gentle kisses along the side of his neck. “i’ll even help you clean yourself out.” 

“huh?!” kai exclaimed, shocking soobin slightly. “what do you mean clean myself out?”

“well, since we’re doing, uh, butt stuff,” soobin began with an awkward giggle, “you need to make sure you’re all clean down there, but don’t worry! hyung has to do it too, so i’ll be with you every step of the way.”

kai’s face burned with embarrassment at the thought of “cleaning himself out.” while soobin’s presence made it less uncomfortable, he just wasn’t sure he could handle it, or so he thought. as soon as yeonjun rid himself of his shirt, kai’s gaze locked onto the blueish red marks littering the expanse of yeonjun’s otherwise flawless skin. 

“w-what are those?” kai muttered, blood reaching a low boil.

“oh, these are just hickeys. soobin has a bad habit of leaving them on me whenever we make out,” yeonjun spoke nonchalantly, unaware of the fire currently burning inside kai.

“i’ll do it,” kai blurted out, causing his brothers to stare at him and each other in shock.

“are you sure, baby? you can have more time to think if you--” yeonjun began before kai cut him off.

“i don’t want to be left out again…” kai trailed off. 

“we never wanted to do this without you!” soobin jumped in. “if you were our age, this would’ve happened a long time ago.” 

“then i want to make up for lost time,” kai said plainly, staring deep into soobin’s eyes with the same desire-laden gaze from earlier that day.

soobin just smiled before stating, “he’s ready.” kai watched with curiosity as soobin grabbed a strange, lightbulb shaped object before taking his hand and leading him to the bathroom. “i’ll get him ready. try to stay hard in the meantime,” soobin told yeonjun with a giggle before disappearing into the bathroom.

yeonjun spent the next little while lazily jerking himself off while listening in on the messy conversation of his younger brothers. after a few minutes, some sparse moans, and a million questions, the duo emerged from the bathroom, completely naked.

“look at you two,” yeonjun mused. “my beautiful little brothers. let’s get you two ready, hm? care to pick out a couple toys?”

kai’s eyes anxiously scanned the selection laid out in front of him. the twins owned everything from tiny, beginner’s plugs to monstrous, extra large dildos. eventually, kai’s gaze landed upon a modest, glass dildo with light pink details and a heart-shaped handle. 

“so pretty,” he whispered, alerting yeonjun that he had made his choice. 

“i knew you’d like this one. i actually bought it hoping i’d get to use it on you someday,” yeonjun gushed while smiling lovingly at kai, who was now blushing furiously. with just a few words, yeonjun somehow managed to make kai feel as though he had always been a part of their sex life, even if only in their desires. 

once soobin had chosen his favourite plug, the two crawled back onto the bed before yeonjun instructed the youngest to get on all fours. kai waited obediently, though a subtle sense of unease still lingered in his gut. yeonjun spread a generous amount of lube on two of his fingers before massaging it into the rim of kai’s ass. 

“feels cold,” kai giggled. yeonjun could sense kai warming up to the situation, so he very slowly pushed one finger inside. the younger boy to arched his back in response. yeonjun was thorough in his ministrations, curling his finger to massage every muscle inside of his baby brother before testing the waters with a second finger. 

meanwhile, soobin had been watching from a distance, indulging in the view as he stretched himself out enough to comfortably wear his favourite plug. once he was ready, soobin crawled towards the moaning mess in front of him.

“you look so cute with yeonjunnie’s fingers in your ass, hueningie!! i bet you’d look even more pretty with my cock in your mouth,” soobin suggested excitedly. “can you do that for hyung?” 

liking the events that were unfolding in front of him, yeonjun stopped fucking his fingers into kai long enough for him to regain composure. kai lifted himself off the bed to stare up at soobin through his long eyelashes and nod confidently. 

“such a good little brother. now, open your mouth and stick your tongue out,” soobin directed before gripping his own cock and gently guiding it into kai’s mouth. “that’s it. now, wrap your lips around it and suck.” 

kai obediently followed his brother’s instructions, causing soobin to release a long, drawn out moan. after a few seconds of watching one little brother suck off the other, yeonjun decided it was time to introduce kai’s chosen toy: the pretty glass dildo. yeonjun tentatively pressed the toy into kai, giving his body time to accept it. kai made no objections and took the toy like it was made for him.

“you’re doing so well, hyuka. hyung’s gonna make you feel so good,” yeonjun cooed as he began fucking his baby brother with the dildo. kai broke away from sucking dick for a moment to release a loud gasp as the toy hit new depths. being the good, obedient brother he is, kai quickly took soobin back into his mouth. each one of kai’s moans crashed like a wave over soobin’s cock. soobin felt his head spin with pleasure until it landed on yet another perverse idea. 

as he let his hands settle in kai’s hair, soobin wondered just how deep his little brother could take him. cautiously, soobin gripped kai’s hair as gently as possible and inched his cock down the younger boy’s willing throat. much to soobin’s surprise, his inexperienced brother didn’t gag or object. instead, he just accepted the cock as if he were soobin’s personal fleshlight. 

soobin tried his hardest not to thrust into kai’s throat, but each time yeonjun pushed the dildo back into kai’s ass, it shot the boy forward ever-so-slightly. the older boy was so close to face fucking his little brother he could taste it, and he wanted more. suddenly, soobin snapped and began thrusting mercilessly into kai’s throat. soobin kept his eyes locked on kai, watching him for signs of discomfort but all he saw was a calm boy with watery eyes. kai was so calm, in fact, that he managed to swallow the spit that had settled in his mouth, causing soobin to pull out with a whimper. 

“did i do something wrong?” kai asked before coughing a few times, saliva dripping from his mouth. kai’s gaze fixated on soobin’s cock as it pulsed and twitched right in front of his face. 

“god, no. you’re perfect, hueningie. did you know that you didn’t have a gag reflex?” soobin managed to say between gasps. 

“yep!” kai said proudly with a smile. 

“you hear that, yeonjunnie? our little baby has a hidden talent! and he looks so cute doing it too!” soobin leaned down to squeeze kai’s cheeks and wipe the tears that had stained his soft flesh. 

“judging by the way you pulled out, i’ll bet the kid gives the best head out of all of us. i’ll have to feel it for myself next time though,” yeonjun spoke as he pulled the dildo out of kai and replaced it with his fingers once more. “right now, i’d much rather see what my dick feels like in here.”

“how does that sound, baby?” yeonjun ran his free hand through kai’s hair before letting it rest upon the small of his back. “ready for your big brother to take your virginity?”

“ready,” kai spoke softly. “i trust you, yeonjun hyung.”

“i’m proud of you, baby,” yeonjun said with a reassuring smile. 

yeonjun finally pulled down his boxers to reveal the achingly hard cock that had been restrained all evening. kai bit his lip at the sight, anticipating the long-awaited sensation of feeling his brother’s cock deep inside of him. 

just as kai heard the sound of the lube bottle closing, a thought popped into his mind that he couldn’t ignore.

“wait! if yeonjun hyung is going to have sex with me...then what’s soobinnie hyung gonna do? that’s not fair,” the youngest pouted.

“show him, soobin,” yeonjun instructed. 

soobin, who had already been sitting on his knees, turned around until his ass faced kai. the younger boy’s eyes went wide as he noticed the fluffy little bunny-like tail that sat nestled between soobin’s cheeks. 

“s-soobinnie? why do you have a bunny tail?” 

“do you like it, huening-ah? why don’t you pull on it and find out?” soobin teased, wagging his ass back and forth. kai tentatively pulled on the fluffy tail until it came loose, leaving soobin gaping in front of his baby brother. “i’m all yours, kai.” 

kai was stunned into silence. the lewd potential of the situation was more than kai’s inexperienced mind could comprehend. 

“i’m gonna help you fuck soobinnie too,” yeonjun explained. “that way no one gets left out.” 

kai shivered at the thought of having sex with both of his brothers at the same time. he was more than ready, kai felt like he was made for this. he was so overwhelmed that a shy, “i love you,” was all kai could muster in the moment.

“we love you too, baby. so much,” yeonjun left gentle kisses along kai’s spine before sitting up to guide his cock into the young boy. 

kai gasped at the sensation, feeling his thighs quiver as yeonjun went deeper and deeper until he was buried to the hilt. 

“fuck,” yeonjun cussed, stilling his hips long enough to regain his composure. “give me your arms, hyuka.” 

kai extended his arms so that yeonjun could pull them until his back sat flush against the older boy’s chest. soobin took the opportunity to assume his position on all fours in front of kai. 

“now, i’m gonna help you fuck soobinnie, okay?” yeonjun whispered breathlessly into kai’s ear, earning another shy yet certain nod. yeonjun placed one hand on kai’s hip, the other wrapping around the young boy’s hard cock. yeonjun rubbed the tip against their brother’s hole until it slipped past the rim. “push your hips forward, baby. that’s it.” kai listened and obeyed, letting his brother’s warmth envelop him until he, too, was buried to the hilt. 

“good boy. i’m gonna start moving, okay? so, just find my rhythm and use it to thrust into soobin,” yeonjun instructed before focusing on his own movements, pulling back only to snap his hips against kai’s ass. 

kai felt a surge of pleasure enter his body with each thrust. the young boy’s hands found purchase on soobin’s soft yet sturdy back, reminding him of his newfound responsibility in this triad: to fuck soobin. once the initial shock wore off, kai began moving in and out of his pliant, cockwarming older brother. 

after a few false starts, kai eventually found a rhythm to compliment yeonjun’s. kai was pleased and amused to discover that he was, in fact, not the loudest of the three, as soobin practically squealed with every thrust. however, that was, until yeonjun began teasing kai’s sensitive nipples, eliciting the loudest moan yet.

“you like that, hyuka? remember how hyung would pinch your nipples when we were kids? i could tell you liked it back then,” yeonjun teased. “knew it got you hard.”

“hyuuuung!! that’s embarrassing,” kai whined, trying desperately to hide his face in soobin’s neck. seeing kai so small and shy made yeonjun’s dick twitch. he knew he was getting close, so yeonjun gripped kai’s waist and quickened his pace. 

“hyuka...gonna make me cum...you’re so tight...feel so good,” yeonjun babbled out praise after praise for his little brother. somehow, yeonjun’s thrusts got faster, causing him to graze kai’s sweet spot. kai’s muscles tightened in response, squeezing yeonjun’s cock until it sent him spiralling without any warning. “f-fuck, kai...cumming.”

yeonjun quivered as he held the young boy’s body still and pumped him full of cum. kai twitched as he experienced the strange yet exhilarating sensation. yeonjun collapsed onto kai’s back and placed gentle, sloppy kisses all over his shoulder.

“fuck soobin silly for me,” yeonjun whispered in kai’s ear with a playful spank before pulling out. “he’s all yours now, soobinnie.”

soobin knew his cue, and he was anxious to act on it. without hesitation, soobin sat up on his knees again before turning around to face kai. 

“huening-ah,” soobin started with his cutesy tone, “why don’t you let hyung do the hard work? after all, it’s still your first time - you deserve it.” soobin wasn’t truly asking anymore, he needed this. “just lie back, and let soobinnie ride you.” 

kai did as he was told, falling back onto the pillows as soobin crawled on top of him. the younger boy watched with wide eyes as soobin grabbed kai’s dick and guided it back inside of him. as soobin sunk down on his little brother’s cock, kai noticed his eyes roll back. 

“d-does it feel good?” kai timidly tried to emulate his brother’s confident speech. soobin couldn’t help the huge, loving smile that painted his face.

“feels like you were made to fit inside me…” soobin held eye contact with kai as he started bouncing slowly. 

“just wanna make you both feel good,” kai pouted as he glanced between the brother on his lap and the brother sitting next to them. 

“you already are, baby,” yeonjun mused. “but, if you wanna do more, i bet soobin would love it if you jerked him off.” 

eager to please, kai swiftly took hold of soobin’s impossibly hard length and started stroking him. soobin closed his eyes out of sheer, unimaginable pleasure before leaning back to hold onto kai’s thighs. from this new angle, kai could feel his cock hitting something that felt...different. sure enough, soobin’s moans went up an octave at the same time. 

“good boy! looks like you found soobinnie’s g-spot,” yeonjun praised and kai felt his ego inflate, causing him to experiment with rocking his hips up to meet soobin’s. 

“o-oh my god, hueni-ing,” soobin hiccuped with pleasure. “feels so good, don’t stop. don’t stop. don’t sto--. fuck.” 

soobin’s orgasm quickly overwhelmed his body, sending him forward to plant his hands on kai’s torso in an effort to stay upright. soobin’s hips shook erratically as he rode out each wave of pleasure, shooting ropes of cum all over kai’s hand. 

before soobin even had time to catch his breath, yeonjun had grabbed kai’s hand and proceeded to lap up all of his cum. yeonjun held his brother’s release in his mouth for a moment as he made eye contact with kai.

“i’m sorry, baby. did you want a taste?” yeonjun offered and kai sheepishly said yes. yeonjun leaned down to meet his little brother in a sloppy kiss. as the cum slipped from yeonjun’s mouth to kai’s, soobin watched the whole ordeal with bated breath, gasping as he noticed something dripping down the side of kai’s cheek. 

“gonna be a good boy and swallow for soobinnie?” yeonjun asked after pulling away from the kiss. 

kai just nodded and swallowed with an audible gulp. 

“how is it that even when you do something that lewd, you’re still the cutest thing i’ve ever seen,” soobin said as he leaned down to lick the rogue cum off kai’s cheek before meeting his lips in a passionate kiss. 

“ahem, soobin,” yeonjun’s voice disturbed their moment. “the poor kid still hasn’t had his orgasm yet. aren’t we being a bit selfish?”

“oh, huening-ah, i’m sorry. you made me feel so good i forgot to return the favour,” soobin frantically apologized. 

in an impressive shift in energy, soobin started riding kai again, causing the young boy to panic.

“n-no, soobin hyung!! doesn’t it hurt to keep going after you cum?” kai says, recalling that one time he accidentally kept humping his pillow after he came.

“not for soobin,” yeonbin informed kai as he placed gentle, encouraging kisses along his neck. “this kid likes to be overstimulated.” 

“weirdo,” kai chirped with a smirk, causing soobin to give him a playful, albeit poorly placed, smack on the chest, or more specifically, on the nipple. kai moaned. 

“says the kid with the sensitive nipples,” soobin retorted. “yeonjun, i think kai deserves some hickeys now. don’t you think?” 

“what a great idea, soobin…” if it weren’t for the mischief in their voices, kai would have been excited for his opportunity to finally be marked by his brothers.

kai’s back arched off the bed as yeonjun trailed his tongue across the younger boy’s shoulder, stopping in a few spots to leave the same dark bruises yeonjun had displayed earlier. the mixture of pain and pleasure was so intoxicating that kai hadn’t even realized where yeonjun was headed until his mouth clamped onto his nipple. 

yeonjun did his best to hold the squirmy boy down as he sucked at kai’s nipple relentlessly. everytime yeonjun managed to swipe his tongue across the tortured bud, kai nearly screamed, feeling every nerve in his body tingle simultaneously. the longer his nipples were stimulated, the more desperate kai became as his hips began bucking up into soobin once again. 

soobin knew kai was nearing his peak, he could feel it in the way kai struggled to find a rhythm, his cock pulsing and throbbing against soobin’s walls every time he stopped. while soobin watched the writhing mess in front of him with delight, he decided it was time to pick up the pace. putting his hips to work, soobin determinedly grinded against kai’s cock in every direction imaginable. 

“hyungs…” kai tried his hardest to whisper out a warning, but the pleasure was too overwhelming. instead, kai just released yet another room-shaking moan as his orgasm struck him. 

yeonjun backed off on the hickeys, choosing to leave gentle kisses along the freshly formed bruises instead. meanwhile, soobin stopped entirely, legs quivering at the feeling of kai’s warmth spreading inside of him. kai, on the other hand, seemed to have all but lost consciousness. the young boy’s body went from a trembling live wire to a limp doll in mere seconds. 

“huening-ah!!” soobin practically squealed. “you came so much!! filled hyung right up!!” 

soobin pushed himself off of kai, accidentally overstimulating the poor boy in the process. kai released a high-pitched whine at the sensation. luckily, soobin didn’t intend on teasing the boy as he was far too focused on savouring the cum in his ass. 

“quick, yeonjunie!! plug me!!” soobin bossed his elder twin around while he remained face down, ass up, with his cheeks spread. 

yeonjun happily obliged, sliding another tail plug into his brother. 

“are you happy now, bunny?” yeonjun asked before petting soobin’s hair. the younger boy nodded enthusiastically, dimples digging deep into his cheeks. 

soobin turned his head to look at the panting mess that kai had become. after showing off and wagging his bushy little tail, soobin crawled across the bed to pull kai’s very tired, very floppy body into a hug.

“you’ve made hyung the happiest bun in the world, hueningie,” soobin cooed. “wanna keep your cum inside me all night!!”

“you’re weird, hyung…” kai giggled, his eyes now fluttering with exhaustion. 

“you know,” yeonjun spoke while assuming his usual position as the big spoon behind kai, “when you’re all tired like this, you kinda feel small again. feels like i’m cuddling our little baby hyuka.”

“i didn’t grow that much,” kai turned his head to stare at yeonjun with furrowed brows and a needy pout. the eldest took the opportunity to steal a gentle kiss.

“you did grow a lot, but that just means we get to share all of this with you,” yeonjun reassured him.

“right,” soobin took a break from sucking on kai’s shoulder to add his not-so-tasteful two cents. “you’re still baby hyuka, we just get to fuck you now.” 

“soobin?”

“yeah?”

“go to sleep,” yeonjun quipped, sending the trio into a brief yet uncontrollable fit of laughter. as their giggles died down, a comfortable silence crept into the room. the brothers simultaneously drifted to sleep, wrapped in each other’s arms on the surface of yeonjun’s tiny twin bed.


End file.
